Amino Acids Proteins, and Enzymes

1. Types of Proteins Amino Acids The Peptide Bond Amino Acids Proteins, and Enzymes

2. Type Examples • Structural tendons, cartilage, hair, nails • Contractile muscles • Transport hemoglobin • Storage milk • Hormonal insulin, growth hormone • Enzyme catalyzes reactions in cells • Protection immune response Types of Proteins

3. Building blocks of proteins • Carboxylic acid group • Amino group • Side group R gives unique characteristics R side chain I H2H—C —COOH I H Amino Acids

4. H I H2N—C —COOH I H glycine CH3 I H2N—C —COOH I H alanine Examples of Amino Acids

5. Nonpolar R = H, CH3, alkyl groups, aromatic O Polar ll R = –CH2OH, –CH2SH, –CH2C–NH2, (polar groups with –O-, -SH, -N-) Polar/Acidic R = –CH2COOH, or -COOH Polar/ Basic R = –CH2CH2NH2 Types of Amino Acids

6. Identify each as (1) polar or (2) nonpolar A. NH2–CH2–COOH (Glycine) CH3 | CH–OH | B. NH2–CH–COOH (Serine) Learning Check AA1

7. Identify each as (1) polar or (2) nonpolar A.(2) NH2–CH2–COOH (Glycine) CH3 | CH–OH | B. (1)NH2–CH–COOH (Serine) Solution AA1

8. 10 amino acids not synthesized by the body • arg, his, ile, leu, lys, met, phe, thr, trp, val • Must obtain from the diet • All in dairy products • 1 or more missing in grains and vegetables Essential Amino Acids

9. Ionization of the –NH2 and the –COOH group • Zwitterion has both a + and – charge • Zwitterion is neutral overall + NH2–CH2–COOH H3N–CH2–COO– glycine Zwitterion of glycine Amino Acids as Acids and Bases

10. H+ OH– + + H3N–CH2–COOHH3N–CH2–COO–H2N–CH2–COO– Positive ionzwitterionNegative ion Low pH neutral pH High pH pH and ionization

11. Amide bond formed by the –COOH of an amino acid and the –NH2 of the next amino acid O CH3 + || + | NH3–CH2–COH + H3N–CH–COO– O CH3 + ||| NH3–CH2–C – N–CH–COO– | peptide bond H The Peptide Bond

12. Amino acids linked by amide (peptide) bonds Gly Lys Phe Arg Ser H2N-end COOH-end Peptide bonds Peptides

13. What are the possible tripeptides formed from one each of leucine, glycine, and alanine? Learning Check AA3

14. Tripeptides possible from one each of leucine, glycine, and alanine Leu-Gly-Ala Leu-Ala-Gly Ala-Leu-Gly Ala-Gly-Leu Gly-Ala-Leu Gly-Leu-Ala Solution AA3

15. Primary and Secondary Structure Tertiary and Quaternary Structure Protein Hydrolysis and Denaturation Amino Acids, Proteins, and Enzymes

16. The particular sequence of amino acids that is the backbone of a peptide chain or protein Primary Structure of Proteins Ala-Leu-Cys-Met

17. Three-dimensional arrangement of amino acids with the polypeptide chain in a corkscrew shape • Held by H bonds between the H of –N-H group and the –O of C=O of the fourth amino acid along the chain • Looks like a coiled “telephone cord” Secondary Structure – Alpha Helix

18. Polypeptide chains are arranged side by side • Hydrogen bonds form between chains • R groups of extend above and below the sheet • Typical of fibrous proteins such as silk Secondary Structure – Beta Pleated Sheet

19. Three polypeptide chains woven together • Glycine, proline, hydroxy proline and hydroxylysine • H bonding between –OH groups gives a strong structure • Typical of collagen, connective tissue, skin, tendons, and cartilage Secondary Structure – Triple Helix

20. Indicate the type of structure as • primary (2) alpha helix • beta pleated sheet (4) triple helix • Polypeptide chain held side by side by H bonds • Sequence of amino acids in a polypeptide chain • Corkscrew shape with H bonds between amino acids • Three peptide chains woven like a rope Learning Check P1

21. Indicate the type of structure as • primary (2) alpha helix • beta pleated sheet (4) triple helix • 3 Polypeptide chain held side by side by H bonds • 1 Sequence of amino acids in a polypeptide chain • 2 Corkscrew shape with H bonds between amino acids • 4 Three peptide chains woven like a rope Solution P1

22. Specific overall shape of a protein • Cross links between R groups of amino acids in chain disulfide –S–S– + ionic –COO– H3N– H bonds C=O HO– hydrophobic –CH3 H3C– Tertiary Structure

23. Globular proteins Fibrous proteins “spherical” shape long, thin fibers Insulin Hair Hemoglobin Wool Enzymes Skin Antibodies Nails Globular and Fibrous Proteins

24. Proteins with two or more chains • Example is hemoglobin Carries oxygen in blood Four polypeptide chains Each chain has a haem group to bind oxygen Quaternary Structure

25. Identify the level of protein structure 1. Primary 2. Secondary • Tertiary 4. Quaternary • Beta pleated sheet • Order of amino acids in a protein • A protein with two or more peptide chains • The shape of a globular protein • Disulfide bonds between R groups Learning Check P3

26. Identify the level of protein structure 1. Primary 2. Secondary 3. Tertiary 4. Quaternary • 2 Beta pleated sheet • 1 Order of amino acids in a protein • 4 A protein with two or more peptide chains D. 3 The shape of a globular protein E. 3 Disulfide bonds between R groups Solution P3

27. Break down of peptide bonds • Requires acid or base and heat • Gives smaller peptides and amino acids • Similar to digestion of proteins using enzymes • Occurs in cells to provide amino acids to synthesize other proteins and tissues Protein Hydrolysis

28. Hydrolysis of a Dipeptide

29. Disruption of secondary, tertiary and quaternary protein structure by heat/organics Break apart H bonds and disrupt hydrophobic attractions acids/ bases Break H bonds between polar R groups and ionic bonds heavy metal ions React with S-S bonds to form solids agitation Stretches chains until bonds break Denaturation

30. Hard boiling an egg • Wiping the skin with alcohol swab for injection • Cooking food to destroy E. coli. • Heat used to cauterize blood vessels • Autoclave sterilizes instruments • Milk is heated to make yoghurt Applications of Denaturation

31. What are the products of the complete hydrolysis of Ala-Ser-Val? Learning Check P4

32. The products of the complete hydrolysis of Ala-Ser-Val are alanine serine valine Solution P4

33. Tannic acid is used to form a scab on a burn. An egg becomes hard boiled when placed in hot water. What is similar about these two events? Learning Check P5

34. Acid and heat cause a denaturation of protein. They both break bonds in the secondary and tertiary structure of protein. Solution P5

35. DNA

36. DNA RNA

37. DNA RNA

38. DNA RNA

39. Alternate phosphate and sugar (deoxyribose), phosphate ester bonds DNA Backbone Structure

40. Alternate phosphate and sugar (deoxyribose), phosphate ester bonds DNA Backbone Structure

41. DNA RNA

42. DNA Primary Structure Summary

43. DNA RNA

44. Base pairing by unique hydrogen bonds • C - G and A - T pairs DNA Double Helix

45. Base pairing by unique hydrogen bonds • C - G and A - T pairs DNA Double Helix

46. DNA

47. Complementary base pairs form new strands. DNA Replication

48. mRNA contains codons which code for amino acids. Types of RNA

49. DNA

50. rRNA - Ribosome - contains enzymes and keeps everything together Types of RNA